May 2001

Got this crazy idea to build a hovercraft.  Actually it didn't just pop into my head.  I have wanted to build one since seeing a Popular Mechanics article on the Yellow Jacket when I was a kid.  The plans were old then.  After much research and many phone calls I decided to build a UH-13P. 

A little bit about me... I am a Software Developer who works here.  I am also a computer geek to the max  see my lab at home here.  I hold a private pilots license and love to fly both full size and remote control craft that I build.  I also love to motorbike.  I am married and have two daughters.  I have always been a handy guy and like to be on the business end of most power tools.

My goal is to complete this craft by the end of August 2001.  Lets see how I do.

Pictured top right is Mike Jacobsons white UH-13P. This is basically what I am building except I am using a belt off the thrust engine to drive the lift fan where as Mike has a 10HP engine to drive his.

Pictured bottom right  is a concept by Zoltan Pittner for the 13P.  I am going to base mine on this design.  Awesome design.  To check out more views of this design click here.

May 2001

May 2001

May 2001

Engine came with new quieter muffler, 3 foot wiring harness and keyswitch.  Awesome Deal.

May 2001

June 1, 2001

June 2, 2001

June 3, 2001

Note: I ended up using the out of the box foam cutter with the nichrome attached on one end.  I attached two 4" c-clamps to the other end of the nichrome and used speaker cable to run the electricity from the other end of the bow to the base of the nichrome on the c-clamp.

June 8, 2001

Sun June 10, 2001

8 Hours

Working with epoxy can sure be messy.  I am glad I bought a 100pak of surgical gloves.  They really came in handy.  I am not sure if I used too much or enough epoxy.  I coated both sides of the foam sheets with a foam 8" roller. 

We will see how well everything went tomorrow...

Mon Jun 11, 2001

1 Hour

Tue Jun 12, 2001

2 hours

With measurement chart in hand I marked the 20 points down each side of the hull with a t push pin.

Next I used a yellow string to run alongside the pins down both sides of the hull. .I put a little tension on the string and secured it to the stern on each side.

I then started using additional tack pins halfway between each pin to gently curve the hull.  This worked excellent. When I was done I ended up with a row of pins roughly 3" apart that held the yellow string that marked the outline of the hull.

I again tensioned the string on each side so it wouldn't move when I ran a marker alongside the outside edge.  I used a Fine Point Sanford Sharpie to mark the line.  Use slight pressure against the string when running it down the line so you don't distort the outline.

When I removed the push pins and string I was very happy with the shape of the hull.  I have to say I used some TLAR engineering (That Looks About Right).  I took Dave Schneider's advice and trusted my eyes.

I will double check the measurements before I cut.

Wed June 13, 2001

1 Hour

Today I cut out the rough outline of the foam.  I left 1/2 - 1" of foam from outline.  I cut one side and part of the other using a hacksaw blade.  It kept bending so I switched to a regular saw.  It actually worked quite well.  I came very close at one point to cutting off more than I wanted to.  This was because the hacksaw blade started to cut on an angle towards the hull.  I didn't have that problem with the large saw.  The cut was a little rougher but not much.

I used a belt sander to bring the edge close to the line in some places as a test of what works best.  I think I will use the belt sander to take it to 1/8" from the line then use a 2x4 block with sandpaper attached to do the rest.

I noticed a few voids between the layers of foam in some places.  The sheets seem solidly bonded together otherwise.  I am not sure if this is something I should be concerned about.  I would hate for the craft to come apart during operation.  I am pretty sure it will be fine once I add the tack strips and laminate the top with 1/8 ply and fiber glass the bottom of the strips to the foam.  I am pretty sure the voids are just near the edges.  I may inject some epoxy into them with a large syringe and small plastic tube if I notice more of them during the shaping process.

 Thu June 14, 2001

0.5 hour

 Fri June 15, 2001

2 hours

 It was taking too long to bring it down to the line (I left too much on my first cut) so I used a hand held hot wire to bring it to 1/4" or less from the line. 

Next I used the Dewalt Random Orbital Sander (see photo) to smooth out the outline and bring it very close to the line 1/16" or less. 

I used a 9" 2x4 block with 150 grit sandpaper to square it out and bring it up to the line.  I am pretty happy with the results.  This is sure a messy step.  I was literally covered from head to toe with foam dust. 

It is actually starting to look like a 13P or at least a giants surfboard.  I realize one thing now.  I need a bigger garage.

Sat June 16, 2001

3 hours

Well I decided on a method to attach the skirt attach strips to the hull.  I used 14 quick clamps.  I am doing one side at a time. I needed to flatten the curve a little at the nose because the wood wouldn't bend the way I wanted it to.  I have a small fortune here invested in quick clamps.  I do have to say it is the most usefull and convenient clamp I have ever owned. 

I will find out how well this method worked in 17 hours when the epoxy cures. 

Tomorrow I will attach the strip on the other side.  After that I will contour the top as laid out on the plans and add the two extra attach strips at the front.  Once this is complete I will lamintate the 1/8" ply to the top of the deck.  Anyone have a mega-vacuum in Edmonton I can borrow?

I better go cut the lawn... at least thats what my wife keeps telling me.

 Sun June 17, 2001

1.5 Hours

 Fathers Day!  My kids got me a really neat stepping stone with their hand and foot prints in it.  In the picture to the right you can barely see my youngest daughter holding a yellow balloon.

I removed the clamps from the previous days glueing.  The bond was excellent. I was nervous that the attach strip would spring off at the front after removing the clamp.

I glued the other skirt attach strip on using the same method.  The middle picture right shows how I clamped the skirt attach strips at the front. 

Mon June 18, 2001

1 hour

I removed the clamps from yesterdays skirt attach strip.  Bond seems very strong.  Today I cut the two front strips that bring the hull up flat after STA 128.  I epoxied on the one pictured to the right.  I am cris-crossing the seams at the tip of the bow.  I will illustrate this later with a picture when it is complete.

I also sanded the back of the craft square. 

I didn't really feel like working on the craft today... I resolved to complete at least one step per day during the week.  Tomorrow I will glue the strip on the other side.

Tue June 19, 2001

1 hour

Picture top right illustrates how I am overlapping the attach strips at the bow.  It looks really messy in the photo - it really isn't.

The middle photo shows the transition point where it goes from flat top to rounded.  This picture didn't turn out well.  The transition is actually smooth not wobbly.

The bottom right photo show the other strip being bonded to the hull

I most likely won't be working on the craft tomorrow as my wife needs me to watch the kids.  On tap for Thursday is the rear skirt attach strip and top strip. 

Wed June 20, 2001

0.25 hour

Pictured to the top right is the nose of the 13P after a rough sanding

Bottom right shows the bow of the 13P after all the attach strips have been attached.

I really recommend a random orbital sander for this project.  It has been very useful.  Definately worth a $100.

Thu June 20, 2001

0.75 hour

Fri June 22, 2001

2 hours

I removed the clamps and the bond for the rear outer skirt attach strip is strong.  I need to add a piece of 1 1/2" x 3/8" strip to the top of this strip so we are flush with the deck.  I made a template from the plans and used it to make each curved side of the attach strip.  This worked really well.  Attaching the strip however was another story.  The strip was either warped or there was some residual epoxy on top of the bottom strip.  There is 1/16" space between the two strips in some places.  I think I used just about every clamp I own and by the way you can't own too many clamps. I considered taking it off and redoing it.  I decided not to as I will be able to fix this with some epoxy and microballoons and a few good sanding sessions.  I have to be careful that I don't get caught trying to be a perfectionist.  After all I am trying to finish this by the end of August. All the attach strips have now been afixed to this craft now.

Tomorrow I will shape the hull top to meet the side attach strips  and sand it flat elsewhere.  I don't think I will be able to laminate tomorrow.  I will plan to do this on Sunday.  I don't want too vacuum bag and go to bed... I want to be up to babysit it.

Note: Purchased another gallon of West Systems epoxy $177